scholarly journals Studies on dimension-eight genuine Quartic Boson Coupling operators

2021 ◽  
Vol 2105 (1) ◽  
pp. 012014
Author(s):  
A. Marantis ◽  
I. Maznas ◽  
K. Kordas ◽  
A. Leisos ◽  
A. Tsirigotis
Keyword(s):  
Vector Boson ◽  
Z Bosons ◽  
Gauge Bosons ◽  
The Standard Model ◽  
Vector Gauge ◽  
Boson Coupling ◽  
Vector Boson Scattering ◽  
Two Jets ◽  
Gauge Boson Couplings ◽  
Source Of Information

Abstract Vector Boson Scattering (VBS) processes provide a great source of information on the structure of the Quartic Gauge Boson Couplings (QGCs). The Standard Model allows self interactions of the charged vector gauge bosons, although vertices with neutral-only bosons are forbidden. In this paper we use Monte Carlo samples containing VBS events with two Z-bosons in association with two jets, and we present preliminary studies for the setting of constraints on anomalous quartic couplings. In these studies we investigate typical kinematic variables and we classify them according to their sensitivity to aQGC effects. Finally, we evaluate the cross-section enhancement by each one of the dimension-eight QGC operators in the ZZjj channel.

scholarly journals Comparing traditional and deep-learning techniques of kinematic reconstruction for polarization discrimination in vector boson scattering

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
M. Grossi ◽  
J. Novak ◽  
B. Kerševan ◽  
D. Rebuzzi
Keyword(s):  
Neural Network ◽  
Deep Neural Network ◽  
Vector Boson ◽  
Higgs Mechanism ◽  
Beyond The Standard Model ◽  
Decay Channels ◽  
Leptonic Decays ◽  
Learning Techniques ◽  
The Standard Model ◽  
Vector Boson Scattering

AbstractMeasuring longitudinally polarized vector boson scattering in $$\mathrm {WW}$$ WW channel is a promising way to investigate unitarity restoration with the Higgs mechanism and to search for possible physics beyond the Standard Model. In order to perform such a measurement, it is crucial to develop an efficient reconstruction of the full $$\mathrm {W}$$ W boson kinematics in leptonic decays with the focus on polarization measurements. We investigated several approaches, from traditional ones up to advanced deep neural network structures, and we compared their abilities in reconstructing the $$\mathrm {W}$$ W boson reference frame and in consequently measuring the longitudinal fraction $$\mathrm {W}_{\text {L}}$$ W L in both semi-leptonic and fully-leptonic $$\mathrm {WW}$$ WW decay channels.

scholarly journals Extension of the standard model of electroweak interaction and Dark Matter in the tangent bundle geometry

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
Joachim Herrmann
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Tangent Bundle ◽  
Electroweak Interaction ◽  
Fiber Axis ◽  
Beyond The Standard Model ◽  
Gauge Bosons ◽  
Quantum Numbers ◽  
The Standard Model ◽  
Vector Gauge

Abstract A generalized theory of electroweak interaction is developed based on the underlying geometrical structure of the tangent bundle with symmetries arising from transformations of tangent vectors along the fiber axis at a fixed spacetime point given by the SO(3,1) group. Electroweak interaction beyond the standard model (SM) is described by the little groups $$ SU(2)\otimes E^{c}(2)$$SU(2)⊗Ec(2) ($$E^{c}(2)$$Ec(2) is the central extended Euclidian group) which includes the group $$SU(2)\otimes U(1)$$SU(2)⊗U(1) as a limit case. In addition to isospin and hypercharge, two additional quantum numbers arise which explain the existence of families in the SM. The connection coefficients yield the SM gauge potentials but also hypothetical gauge bosons and other hypothetical particles as a Higgs family as well as candidate Dark Matter particles are predicted. Several important consequences for the interaction between dark fermions, dark scalars or dark vector gauge bosons with each other and with SM Higgs and Z-bosons are described.

VECTOR BOSON DOMINANCE OF ELECTROWEAK INTERACTIONS

1993 ◽  
Vol 08 (33) ◽  
pp. 3129-3138 ◽  
Author(s):  
YU. F. PIROGOV
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Vector Boson ◽  
Local Symmetry ◽  
Higgs Bosons ◽  
Quantum Field ◽  
Gauge Bosons ◽  
The Standard Model ◽  
Vector Bosons ◽  
Common Substructure

The linearization of the nonlinear standard model G/H= SU(3) L × U(1)/SU(2) L × U(1) via the hidden local symmetry H loc = SU(2) L × U(1) is considered. Mixing of the light elementary gauge bosons of the standard model with the dynamically generated heavy composite vector bosons is studied under the hypothesis of vector boson dominance. The model is theoretically consistent as quantum field theory and phenomenologically acceptable. It can be used as a guide to study systematically the deviations from the standard model due to a common substructure of leptons, quarks and Higgs bosons.

scholarly journals Polarized Z bosons from the decay of a Higgs boson produced in association with two jets at the LHC

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Ezio Maina ◽  
Giovanni Pelliccioli
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Vector Boson ◽  
Z Bosons ◽  
Gluon Fusion ◽  
Gauge Sector ◽  
Fully Differential ◽  
Higgs Decay ◽  
Four Leptons ◽  
Two Jets

AbstractInvestigating the polarization of weak bosons provides an important probe of the scalar and gauge sector of the Standard Model. This can be done in the Higgs decay to four leptons, whose Standard-Model leading-order amplitude enables to generate polarized observables from unpolarized ones via a fully-differential reweighting method. We study the $$\text {Z} $$ Z -boson polarization from the decay of a Higgs boson produced in association with two jets, both in the gluon-fusion and in the vector-boson fusion channel. We also address the possibility of extending the results of this work to higher orders in perturbation theory.

scholarly journals ρ PARAMETER IN THE VECTOR CONDENSATE MODEL OF ELECTROWEAK INTERACTIONS

1994 ◽  
Vol 09 (18) ◽  
pp. 1701-1705 ◽  
Author(s):  
G. CYNOLTER ◽  
E. LENDVAI ◽  
G. POCSIK
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Vector Boson ◽  
Higgs Doublet ◽  
Electroweak Interactions ◽  
Gauge Bosons ◽  
Momentum Scale ◽  
The Standard Model ◽  
Vector Bosons

In the standard model of electroweak interactions the Higgs doublet is replaced by a doublet of vector bosons and the gauge symmetry is broken dynamically. This generates masses for the gauge bosons and fermions as well as it fixes the interactions in the model. The model has a low momentum scale. In this note we show that the model survives the test of the ρ parameter, and to each momentum scale ρ chooses a possible range of vector boson masses.

scholarly journals Study of Vector Boson Scattering and Search for New Physics in Events with Two Same-Sign Leptons and Two Jets

2015 ◽  
Vol 114 (5) ◽  
Author(s):  
V. Khachatryan ◽  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Vector Boson ◽  
New Physics ◽  
Vector Boson Scattering ◽  
Two Jets

scholarly journals A Machine Learning approach to the EFT re-interpretation of the WZjj fully leptonic electroweak production

2021 ◽  
Vol 2105 (1) ◽  
pp. 012011
Author(s):  
Konstantinos Bachas ◽  
Ioannis Karkanias ◽  
Eirini Kasimi ◽  
Christos Leonidis ◽  
Chara Petridou ◽  
...  
Keyword(s):  
Machine Learning ◽  
Standard Model ◽  
Vector Boson ◽  
New Physics ◽  
Effective Field ◽  
Machine Learning Techniques ◽  
Atlas Collaboration ◽  
The Standard Model ◽  
Two Jets ◽  
Integrated Luminosity

Abstract In this paper we study the use of Machine Learning techniques to set constraints on indirect signatures of physics beyond the Standard Model in Vector Boson Scattering (VBS), in the electroweak (EWK) production of self-interacting W ± Z bosons in association with two jets. The WZ fully leptonic channel has been extensively studied by the ATLAS Collaboration at the LHC and we are about to provide results using the full Run 2 data corresponding to an integrated luminosity of 139fb −1. The EWK production of the WZ in association with two jets has been already observed at 36fb −1 with an observed significance of 5.3 standard deviations. A factor of four increase in the integrated luminosity provides an opportunity to check for deviations from the Standard Model (SM) predictions, in particular for model independent, indirect searches for New Physics. Such searches can be realized in the context of an extension of the SM in terms of an Effective Field Theory (EFT) formalism, providing a way to quantify possible deviations from the Standard Model. The EFT Lagrangian besides the Standard Model terms comprises contributions from higher dimension operators, their effect being determined by the strength of their corresponding parameters (Wilson coefficients scaled to the appropriate power of Λ, indicating the scale of the appearance of New Physics). In this paper an attempt is made to search for New Physics effects in the WZjj production, using state-of-the-art machine learning models where diverse network architectures are effectively combined into ensembles trained on the outcomes of base learners maximizing performance. The base learners are trained to identify pure WZjj signal events originating from the effect of EFT operators, from WZjj background events originating from strong (QCD) or EWK WZjj processes. We investigate the utilization of the ensemble model response in estimating the sensitivity of WZjj events in some of the dimension-8 EFT operators and compare the results to sensitive kinematic variables traditionally used to constrain the EFT operator effects.

scholarly journals Recent observation and measurements of diboson processes from the ATLAS experiment

2020 ◽  
Vol 35 (28) ◽  
pp. 2030013
Author(s):  
Yee Chinn Yap
Keyword(s):  
Recent Observation ◽  
Production Cross ◽  
New Physics ◽  
Inclusive Production ◽  
Centre Of Mass ◽  
Atlas Experiment ◽  
The Standard Model ◽  
Electroweak Sector ◽  
Two Jets ◽  
Gauge Boson Couplings

This review covers results at a centre-of-mass energy of [Formula: see text] TeV from the ATLAS experiment that have been published, or submitted for publication, up to April 2020. It summarizes results on the inclusive production cross-section measurements of boson pairs and of the electroweak production of diboson in association with two jets. The measurements either use the full integrated luminosity of 139 fb[Formula: see text] collected by the ATLAS detector at the LHC from 2015 to 2018, or a partial dataset of 36 fb[Formula: see text]. The inclusive production rates of diboson are studied to high precision. These measurements provide stringent tests of the electroweak sector of the Standard Model and allow search for new physics via anomalous triple and quartic gauge boson couplings.

NEW NEUTRAL GAUGE BOSONS AT HIGH ENERGY e+e− COLLIDERS

1989 ◽  
Vol 04 (17) ◽  
pp. 4551-4565 ◽  
Author(s):  
JOANNE L. HEWETT ◽  
THOMAS G. RIZZO
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Z Bosons ◽  
High Energy ◽  
Beam Polarization ◽  
Gauge Bosons ◽  
Final State ◽  
The Standard Model ◽  
Model Predictions ◽  
Coupling Parameters

We discuss and contrast search limits for and properties of new Z′ gauge bosons which can be probed at high energy e+e− colliders within the context of several E6 superstring-inspired models. In particular, we discuss the probability of distinguishing these various models from one another and determining the Z′ coupling parameters uniquely. Using the deviations from the standard model predictions for asymmetries and cross sections for various final state fermions, we set discovery limits for new Z′ bosons at [Formula: see text] and 1 TeV e+e− colliders. We find quite generally that cross section deviations provide the strongest limits on the existence of new Z′ bosons below threshold even when 100% beam polarization is available. The possibility of using Z′ pair production as a sensitive probe of the e+e−Z′ coupling is also examined.

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